Evaluating a Novel Cell-Free Preservation Solution for Human Cardiomyocyte Protection: A Proof-of-Concept Study

Heart transplantation remains the definitive therapy for end-stage heart failure; however, its clinical impact is constrained by donor availability and preservation-associated injury. Static cold storage (SCS) with cardioplegic solutions such as Custodiol is the current clinical standard of care, yet extended cold ischemia markedly increases the risk of primary graft dysfunction. There is therefore a critical need for advanced preservation strategies and solutions that maintain graft viability under both cold and normothermic conditions.

This study is aimed at comparing the effects of Custodiol and the novel cell-free organ preservation solution Omnisol on contractile function, metabolic activity, and apoptosis in human cardiomyocytes under static cold and normothermic storage conditions.

Human-induced pluripotent stem cell-derived cardiomyocytes were subjected to static cold or normothermic storage in standard culture medium, Custodiol, or Omnisol, followed by functional assessment after return to standard culture medium. Contractile function was quantified using video-based motion analysis (MuscleMotion), metabolic activity was quantified by MTT assay, and cell death-associated DNA fragmentation was assessed by TUNEL staining in combination with cell morphology.

Following normothermic preservation in Omnisol, cardiomyocyte contractility was comparable to that observed with standard culture medium, whereas Custodiol-preserved cells showed markedly reduced beating frequency, impaired contraction profiles, and delayed functional recovery. After SCS, contractile function recovered to a similar extent in Omnisol- and Custodiol-treated cells upon return to standard medium. Importantly, Omnisol-treated cardiomyocytes displayed significantly higher metabolic activity than Custodiol-treated cells under both cold and normothermic storage conditions. Apoptosis rates were comparable between groups following cold storage; however, under normothermic conditions, Custodiol treatment was associated with a significant increase in apoptotic cell death.

This proof-of-concept study demonstrates the preservation potential of the novel cell-free preservation solution Omnisol for human cardiomyocytes under static cold and normothermic conditions. These hypothesis-generating findings support further evaluation of Omnisol as a versatile preservation solution for dynamic organ perfusion strategies.